If you've had a root canal, you remember the holders the dentist screws onto healthy teeth, to hold the plastic shield. He then pokes a hole in the plastic, around the one tooth that needs the work.
LOL. I can't do the definition thing, but I can tell you what something is used for.
Sorry Jotmo. ;-)
I always thought there was more to it than that time Tiffany Thiessen kissed that other girl in the hottub.....
:-P